Incandescent mantle.



JOI-IN B. HLPWELL, 0F PHILADELPHIA, PENNSYLVANIA.

INCANDESCENT MANTLE.

Specieation of Letters Patent.

Patented Oct. 1 1912.

Application filed September 7, 1911. Serial No. 648,043.

To all whom it may concern:

Be it known that I, JOHN B. HIPWELL, a citizen of the United States, and aresident o-f the city of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Incandescent Mantles, of which the following is a specification.

My invention vrelates to mantles or incandescents employed in connection with gas burning devices.

Heretofore tubularly knitted fabric has been commonly employed to produce these; but in order to form the closed-end portion of the mantle one end of the tubular fabric has ordinarily been either drawn together or seamed so as to produce an uneven surface and unequal thickness of material.

The main purpose of my invention is to provide a superior mantle without subsequent bunching, folding, or ridging of the fabric; and it consists in a mantle having a seamless tubular body with a hemi-spherical closed end formed throughout by continuous thread, as hereafter fully described, and the essential novelty of which is specitically defined in the claims.

Figure 1 indicates the novel construction of my improved mantle fabric as it appears when practically flattened by sharply bending the same on the line 1-1 of Fig. 3. Fig. 2 shows my mantle attached to an ordinary supporting ring f. Fig. 3 is a plan View of the closed-end of the finished mantle.

The novel features of construction which characterize my improved mantle fabric, and the essential manner of producing the same, are indicated somewhat diagrammatically, but so as to be clearly understood in View of the well-known knitting operations referred to in describing the same.

The wales of the knitted fabric are indicated by stripes bearing the reference letters a and a respectively; all of which Wale stripes extend, in a general way longitudinally of the fabric, as usual, but certain of which, as shown, extend around the closedend of the fabric in continuous lines and parallel planes, as indicated at a a a, so as to form a curved connecting band of wales continuous with those of the tubular body portion of the mantle; while other wales, a a a are deflected at junction lines b or b forming separated connecting-loop seams lying in a great circle of the hemi-spherical closed-end thus formed on the fabric, which circle lies in a plane at right angles to the band formed by the wales a a a.

The seamless mantle is formed as follows: A knitting cylinder of proper diameter is employed having means to throw out of action half the needles or less than half in said cylinder, means to raise out of action consecutive end ones of the active needles during reciprocating movement of a cam cylinder to reduce gradually the number of active needles employed, and means to return said needles during further reciprocating movement of the cam cylinder until the original active needles are again in operation. This reducing and increasing of the active needles employed effects the usual narrowing and widening of the fabric.

In making my improved fabric the machine is set to reciprocate and approximately half or less than half the needles are raised to inoperative position, thread is then supplied to the remaining active needles and several courses are knitted on them, for convenience later in transferring to the idle needles. The narrowing mechanism is now thrown in and the width of the fabric reduced to any desired point, when the widening is started and the fabric increased in width to its original number of needles. This narrowing and widening on half the needles forms the integrally knit closed spherical end Z of the mantle, and it only remains to put the first knit courses, which comprise as many loops as there are idle needles, upon the latter which are now put into action,-the eXtra courses first knit facilitating the transfer of these loops to the idle needles in the cyll indei'-, change the reciprocating movement of the cam cylinder to a continuous rotary movement, and proceed to knit the tubular part a' of the mantle. The closed-end tubular fabric produced is thus completely formed by a continuous knitted thread; is entirely seamless in the tubular body portion which may be made of any desired length, and provided only with connectingloop seams b b in the hemi-spherical portion, so as to have a uniform thickness and a smooth surface both interiorly and exteriorly throughout; and is so symmetrically and strongly formed as to insure practically equal stress and strength, both when being subjected to the usual mounting, burning, shaping and coating operations incident to their conversion into incandescents, and

when subjected to the stress of shipping and actual service.

The specific construction shown may obviously be changed within the spirit of my invention as defined in the claims.

l/Vhat I claim is Y l. A gas ma-ntle embodying a knitted fabric completely formed throughout by a continuous thread and having a seamless tubular body portion, and a seamlessly connected heini-spherical Closing-end of the same texture as said tubular body but comprising narrowing portions formed by the interlocking of the wales.

2. A gas mantle embodying a knitted fabric completely formed throughout by a continuous thread and lhaving a seamless tubular body portion, and a seamlessly connected hemi-sphercal closing-end portion of the same texture as said body portion comprising a body-connecting band having parallel wales extending continuous with those of the tubular body and narrowing portions /formed by the interlocking of the other wales in a diametral plane at right angles to the continuous wales.

In testimony whereof, I afiX my signature, n the presence of two witnesses.

JOHN B. HIPWELL. Witnesses:

D. M. STEWART, WV. G. STEWART.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

- Washington, ID. C. 

